Backport of the new option parser from 2.3

* configure.ac (GPGRT_ENABLE_ARGPARSE_MACROS): Define.
* common/argparse.c, common/argparse.h: Rewrite.
* tests/gpgscm/main.c: Switch to the new option parser.

* g10/gpg.c: Switch to the new option parser and enable a global conf
file.
* g10/gpgv.c: Ditto.
* agent/gpg-agent.c: Ditto.
* agent/preset-passphrase.c: Ditto.
* agent/protect-tool.c: Ditto.
* scd/scdaemon.c: Ditto.
* dirmngr/dirmngr.c: Ditto.
* dirmngr/dirmngr_ldap.c: Ditto
* dirmngr/dirmngr-client.c: Ditto.
* kbx/kbxutil.c: Ditto.
* tools/gpg-card.c: Ditto.
* tools/gpg-check-pattern.c: Ditto.
* tools/gpg-connect-agent.c: Ditto.
* tools/gpg-pair-tool.c: Ditto.
* tools/gpg-wks-client.c: Ditto.
* tools/gpg-wks-server.c: Ditto.
* tools/gpgconf.c: Ditto.
* tools/gpgsplit.c: Ditto.
* tools/gpgtar.c: Ditto.
* g13/g13.c: Ditto.
* g13/g13-syshelp.c: Ditto.  Do not force verbose mode.
* sm/gpgsm.c: Ditto. Add option --no-options.
--

This is backport from master

commit cdbe10b762
commit ba463128ce
commit 3bc004decd
commit 2c823bd878
commit 0e8f6e2aa9

but without changing all functions names to gpgrt.  Instead we use
wrapper functions which, when building against old Libgpg-error
versions, are implemented in argparse.c using code from the current
libgpg-error.  This allows to keep the dependency requirement at
libgpg-error 1.27 to support older distributions.  Tested builds
against 1.27 and 1.40-beta.

Note that g13-syshelp does not anymore default to --verbose because
that can now be enabled in /etc/gnupg/g13-syshelp.conf.

GnuPG-bug-id: 4788
Signed-off-by: Werner Koch <wk@gnupg.org>

g13/g13.c

@@ -15,6 +15,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <https://www.gnu.org/licenses/>.
+ * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
 #include <config.h>
@@ -138,7 +139,7 @@ static ARGPARSE_OPTS opts[] = {
 
   ARGPARSE_s_n (oDryRun, "dry-run", N_("do not make any changes")),
 
-  ARGPARSE_s_s (oOptions, "options", N_("|FILE|read options from FILE")),
+  ARGPARSE_conffile (oOptions, "options", N_("|FILE|read options from FILE")),
 
   ARGPARSE_s_s (oDebug, "debug", "@"),
   ARGPARSE_s_s (oDebugLevel, "debug-level",
@@ -163,7 +164,7 @@ static ARGPARSE_OPTS opts[] = {
   ARGPARSE_s_n (oNoVerbose, "no-verbose", "@"),
   ARGPARSE_s_n (oNoSecmemWarn, "no-secmem-warning", "@"),
   ARGPARSE_s_n (oNoGreeting, "no-greeting", "@"),
-  ARGPARSE_s_n (oNoOptions, "no-options", "@"),
+  ARGPARSE_noconffile (oNoOptions, "no-options", "@"),
   ARGPARSE_s_s (oHomedir, "homedir", "@"),
   ARGPARSE_s_s (oAgentProgram, "agent-program", "@"),
   ARGPARSE_s_s (oGpgProgram, "gpg-program", "@"),
@@ -235,9 +236,11 @@ my_strusage( int level )
 
   switch (level)
     {
+    case  9: p = "GPL-3.0-or-later"; break;
     case 11: p = "@G13@ (@GNUPG@)";
       break;
     case 13: p = VERSION; break;
+    case 14: p = GNUPG_DEF_COPYRIGHT_LINE; break;
     case 17: p = PRINTABLE_OS_NAME; break;
     case 19: p = _("Please report bugs to <" PACKAGE_BUGREPORT ">.\n");
       break;
@@ -343,12 +346,10 @@ main ( int argc, char **argv)
   gpg_error_t err = 0;
   /* const char *fname; */
   int may_coredump;
-  FILE *configfp = NULL;
-  char *configname = NULL;
-  unsigned configlineno;
-  int parse_debug = 0;
+  char *last_configname = NULL;
+  const char *configname = NULL;
+  int debug_argparser = 0;
   int no_more_options = 0;
-  int default_config =1;
   char *logfile = NULL;
   int greeting = 0;
   int nogreeting = 0;
@@ -360,8 +361,6 @@ main ( int argc, char **argv)
   struct server_control_s ctrl;
   strlist_t recipients = NULL;
 
-  /*mtrace();*/
-
   early_system_init ();
   gnupg_reopen_std (G13_NAME);
   set_strusage (my_strusage);
@@ -395,29 +394,31 @@ main ( int argc, char **argv)
   pargs.argc = &argc;
   pargs.argv = &argv;
   pargs.flags= 1|(1<<6);  /* Do not remove the args, ignore version.  */
-  while (arg_parse( &pargs, opts))
+  pargs.flags= (ARGPARSE_FLAG_KEEP | ARGPARSE_FLAG_NOVERSION);
+  while (gnupg_argparse (NULL, &pargs, opts))
     {
-      if (pargs.r_opt == oDebug || pargs.r_opt == oDebugAll)
-        parse_debug++;
-      else if (pargs.r_opt == oOptions)
-        { /* Yes, there is one, so we do not try the default one but
-             read the config file when it is encountered at the
-             commandline.  */
-          default_config = 0;
-	}
-      else if (pargs.r_opt == oNoOptions)
-        default_config = 0; /* --no-options */
-      else if (pargs.r_opt == oHomedir)
-        gnupg_set_homedir (pargs.r.ret_str);
+      switch (pargs.r_opt)
+        {
+        case oDebug:
+        case oDebugAll:
+          debug_argparser++;
+          break;
+
+        case oHomedir:
+          gnupg_set_homedir (pargs.r.ret_str);
+          break;
+        }
     }
+  /* Reset the flags.  */
+  pargs.flags &= ~(ARGPARSE_FLAG_KEEP | ARGPARSE_FLAG_NOVERSION);
 
   /* Initialize the secure memory. */
   gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
   maybe_setuid = 0;
 
   /*
-     Now we are now working under our real uid
-  */
+   * Now we are now working under our real uid
+   */
 
   /* Setup malloc hooks. */
   {
@@ -440,47 +441,39 @@ main ( int argc, char **argv)
   ctrl.no_server = 1;
   ctrl.status_fd = -1; /* No status output. */
 
-  /* Set the default option file */
-  if (default_config )
-    configname = make_filename (gnupg_homedir (), G13_NAME".conf", NULL);
+  /* The configuraton directories for use by gpgrt_argparser.  */
+  gnupg_set_confdir (GNUPG_CONFDIR_SYS, gnupg_sysconfdir ());
+  gnupg_set_confdir (GNUPG_CONFDIR_USER, gnupg_homedir ());
 
   argc        = orig_argc;
   argv        = orig_argv;
   pargs.argc  = &argc;
   pargs.argv  = &argv;
-  pargs.flags =  1;  /* Do not remove the args.  */
-
- next_pass:
-  if (configname)
-    {
-      configlineno = 0;
-      configfp = gnupg_fopen (configname, "r");
-      if (!configfp)
-        {
-          if (default_config)
-            {
-              if (parse_debug)
-                log_info (_("Note: no default option file '%s'\n"), configname);
-            }
-          else
-            {
-              log_error (_("option file '%s': %s\n"),
-                         configname, strerror(errno));
-              g13_exit(2);
-            }
-          xfree (configname);
-          configname = NULL;
-        }
-      if (parse_debug && configname)
-        log_info (_("reading options from '%s'\n"), configname);
-      default_config = 0;
-    }
-
+  pargs.flags |=  (ARGPARSE_FLAG_RESET
+                   | ARGPARSE_FLAG_KEEP
+                   | ARGPARSE_FLAG_SYS
+                   | ARGPARSE_FLAG_USER);
   while (!no_more_options
-         && optfile_parse (configfp, configname, &configlineno, &pargs, opts))
+         && gnupg_argparser (&pargs, opts, G13_NAME EXTSEP_S "conf"))
     {
       switch (pargs.r_opt)
         {
+        case ARGPARSE_CONFFILE:
+          {
+            if (debug_argparser)
+              log_info (_("reading options from '%s'\n"),
+                        pargs.r_type? pargs.r.ret_str: "[cmdline]");
+            if (pargs.r_type)
+              {
+                xfree (last_configname);
+                last_configname = xstrdup (pargs.r.ret_str);
+                configname = last_configname;
+              }
+            else
+              configname = NULL;
+          }
+          break;
+
 	case aGPGConfList:
 	case aGPGConfTest:
           set_cmd (&cmd, pargs.r_opt);
@@ -538,17 +531,6 @@ main ( int argc, char **argv)
         case oStatusFD: ctrl.status_fd = pargs.r.ret_int; break;
         case oLoggerFD: log_set_fd (pargs.r.ret_int ); break;
 
-        case oNoOptions: break; /* no-options */
-        case oOptions:
-          /* Config files may not be nested (silently ignore them).  */
-          if (!configfp)
-            {
-              xfree(configname);
-              configname = xstrdup (pargs.r.ret_str);
-              goto next_pass;
-	    }
-          break;
-
         case oHomedir: gnupg_set_homedir (pargs.r.ret_str); break;
 
         case oAgentProgram: opt.agent_program = pargs.r.ret_str;  break;
@@ -592,12 +574,16 @@ main ( int argc, char **argv)
           break;
 
         default:
-          pargs.err = configfp? ARGPARSE_PRINT_WARNING:ARGPARSE_PRINT_ERROR;
+          if (configname)
+            pargs.err = ARGPARSE_PRINT_WARNING;
+          else
+            pargs.err = ARGPARSE_PRINT_ERROR;
           break;
 	}
     }
+  gnupg_argparse (NULL, &pargs, NULL);  /* Release internal state.  */
 
-  /* XXX Construct GPG arguments.  */
+  /* Construct GPG arguments.  */
   {
     strlist_t last;
     last = append_to_strlist (&opt.gpg_arguments, "-z");
@@ -607,21 +593,15 @@ main ( int argc, char **argv)
     (void) last;
   }
 
-  if (configfp)
-    {
-      fclose (configfp);
-      configfp = NULL;
-      /* Keep a copy of the config filename. */
-      opt.config_filename = configname;
-      configname = NULL;
-      goto next_pass;
-    }
-  xfree (configname);
-  configname = NULL;
-
-  if (!opt.config_filename)
+  if (!last_configname)
     opt.config_filename = make_filename (gnupg_homedir (),
-                                         G13_NAME".conf", NULL);
+                                         G13_NAME EXTSEP_S "conf",
+                                         NULL);
+  else
+    {
+      opt.config_filename = last_configname;
+      last_configname = NULL;
+    }
 
   if (log_get_errorcount(0))
     g13_exit(2);
@@ -659,7 +639,9 @@ main ( int argc, char **argv)
   if (logfile)
     {
       log_set_file (logfile);
-      log_set_prefix (NULL, GPGRT_LOG_WITH_PREFIX | GPGRT_LOG_WITH_TIME | GPGRT_LOG_WITH_PID);
+      log_set_prefix (NULL, (GPGRT_LOG_WITH_PREFIX
+                             | GPGRT_LOG_WITH_TIME
+                             | GPGRT_LOG_WITH_PID ));
     }
 
   if (gnupg_faked_time_p ())